Electromagnetic actuator



March 20, 1951 R. B. IMMEL 2,546,000

ELECTROMAGNETIC ACTUATOR' WITNEssEs;

, INVENTOR WW2/4i- /le Y a/phmme/ l BY ATTORNEY March 20, 1951 R. B. IMMEL 2,546,000

ELECTROMAGNETIC ACTUATOR Filed Jan. lO, 1948 2 Sheets-Shea?. 2

INVENTOR 20" f-pbbfmme BYCAM.

ATTORNEY Patented Mar. 20, 1951 UNITED STATES PATENT`OFFICE' ELECTROMAGNETIC ACTUATOR Ralph B. Immel, Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application January 10, 1948, Serial No. 1,592

1 6 Claims.

My invention relates to electromagnetic contactors and is especially concerned with the pivot bearing and movable Contact and armature assembly of such contactors.

In contactors of conventional design, the movable structure, comprising the magnet armature and the movable contacts, is fulcrumed about a pivot bearing of fixed position relative to the stationary contactor structure. For instance, there are contactors whose movable assembly is pivoted by means or" a knife-edge bearing bar which is rigidly mounted on the magnet support bracket of the contactor.

An appreciable cost item in the manufacture of such contactors is due to the fact that slight deviations of the individual parts from the Correct dimensions and the accumulation of tolerances in the completed assembly may result in too little or too much Contact overtravel so that the number of rejects is appreciable, and it is also inieasible to salvage all parts or" contactors ejected for such deficiencies.

It is an object of my invention to greatly reduce or substantially eliminate these shortcomings of the known contactors and to make it pos- '3' sible that all contactors manufactured on an assembly line can be set for a desired value of overtravel.

It is also an object of the invention, relating to multi-pole contactors, to permit adjusting the different movable contacts of a contactor so that all moving contacts touch the res ective stationary contacts simultaneously.

Another and subsidiary object of my invention is to achieve these results with the aid of structural means of utmost simplicity and minimum space requirements in order to secure appreciable overall savings in cost over the known contactors of otherwise comparable type and rating.

According to my invention, I provide the contactors with a knife-edge type bearing structure whose stationary bearing member, pivotally engaged by the movable contact and armature assembly, is displaceable relative to the magnet and the stationary contacts approximately in parallel to the direction of contact overtravel, and I provide fastening means for permanently securing Athe stationary bearing member in an adjusted position.

According to another feature of my invention, I provide the displaceable bearing structure with the stationary abutment for the armature biasing spring so that the positional relation of the spring and the magnitude and direction of its biasing force relative to the movable assembly are not anected by positional changes of the bearing structure.

These and more specific objects and features of my invention will be apparent from the following description of the embodiment shown in the drawings, in which:

Figure 1 is a lateral and part-sectional View of a contactor according to the invention, while Figs- 2 to 8 show details of the same contactor; more specifically Y Fig. 2 is a top view of a magnet bracket;

Fig 3 is a top view of a bearing bracket, assembled with a sectionally shown cradle structure;

Fig. 4 is a partial top View of the cradle structure, and Fig. 5 is a partial front view of the same structure Fig. G is a bottom view of a spring abutment member appertaining to the cradle structure;

Fig. 7 is a lateral view of the magnet bracket assembled with the bearing bracket, the latter being shown in an adjustment different from that illustrated in Fig. l; and

Fig. 8 is a partial top view of the parts shown in Fig. 7.

All foregoing references to top, bottom and lateral views are based on the showing of Fig. 1 which represents the contactor in the normal position in which it is to be used, the magnet being assumed to be energized and the contacts being closed in opposition to the armature bias.

According to Fig. l, the contactor has a base plate I to be mounted on a panel or other support. An insulator 2 is rmly secured to the base I and carries stationary contacts 3 and 4. A movable contact member 5 bridges the stationary contacts 3 and 4 when in the illustrated closed position. The contact member 5 is mounted in a stirrup-shaped guide member 6 which is attached to the insulating ybody l of an armature assembly. A coiled contact springI 8 disposed in the guide member 5 biases the movable contact member E away from the insulating body l. The body l is firmly secured to a cradle structure e of sheet metal which is pivoted forangular motion about a stationary pivot edge extending perpendicularly to the plane of illustration at the point surrounded in Fig. 1 by a broken circle denoted by i0. A magnet armature H is pivoted to the cradle structure 9 at l2 for limited angular motion relative to the structure S and is biased toward center position by a leaf spring I3. The electromagnet of the contactor has a laminated frame structure I4 equipped with a coil i5 and fastened to the base i by means of pivot edge I and a projecting lug 39.

- and abuts against the bracket I1. tion 2| of the bearing bracket I8 `has a button- Y hole opening 43 and a marginal opening 44 (Fig.

brackets I6 and I1. A bearing bracket I8 is located adjacent the bearing bracket I1. The bracket I8 is adjustable relative to the base I by means of adjusting screws, such as the one shown at I9 in Fig. 1, and is attached to the magnet bracket I1 by fastening screws 28 and 2G (Figs. 1 to 3, '7, 8). The foot portion 2i of the bearing bracket I8 adjacent to the base I is provided with an abutment 22 for an armature biasing or kickot spring 23 whose other end engages an abutment 24 associated with the cradle structure 9 o the armature assembly. i

According to Fig. 2, the magnet bracket I1 has two elongated openings 25 and 25' for the passage of the respective fastening screws 28 and 28. Two lugs 26 and 26 of the magnet bracket I1 have threaded bores for receiving respective screws 21 and 21 which fasten the magnet frame I4 to the bracket (Figs. 1, 2).

The bearing bracket I8, according to Fig. 3, has

"threaded bores for receiving the fastening screws and 20. Due to the elongated shape of openings and 25' in bracket I1, the bearing bracket "portion 28 (Fig. 3) and two lateral arms 29 and 29 so as to have the general shape of the letter T. The arm 29 of the T-shaped bracket portion is provided with the above-mentioned pivotv Vedge I9 which is interrupted by a projecting lug 30 (Fig. 3). The arm 29 has a corresponding The two edges IIJ and IIJ' are in alignment with each other.

The cradle structure 9 appertainingto the mov- `vlable armature assembly forms abutmentsy 3I and 32 (Figs. 1, 4, 5) for holding the armature centering spring I3 (Fig. 1) in proper position and is also equipped with two small flanges 33, 33' and two large flanges 34 and 34 (Figs. 1, 3, 4, 5).

The part of the cradle structure having the large anges 34, 34 straddles the bracket I1 as well as the bearing bracket I8.

opening 35 engaged by the lug 30 of the bearing bracket I8 (Figs. 3, 5). 1) has a corresponding opening 35 engaged by The flange 34 has .an

The flange 34 (Fig.

the lug 30 (Fig. 3). The flanges 34 and 34' are The ange 34 as shown flange 34 has a corresponding notch (not shown).

These two notches receive the ends of a separate abutment member 39 (Fig. 6) which is provided with the above-mentioned abutment 24 forthe kick-out spring 23 (Figs. 1, 6). holds the abutment member 39 in engagement with the cradle structure 9. It also biases the cradle structure into proper engagement with the pivot edges I8 and I0 and biases the armature assembly toward the contact opening position.

The bearing Ibracket I8 has a projection42 (Figs. 1, 7, 8) which serves as a spacing element The foot por- 8) The adjusting screw I9 has a shoulder por- The reduced portion of the screw The spring 23" 4 and is fastened in properly adjusted position by means of a locking nut 46 (Figs. l, '7). A second fastening screw similar to the one denoted by I9 i has a reduced diameter portion which engages the marginal opening 44 and is bordered by a head 45. The second screw is also threaded through the base I and secured in properly adjusted position by means of a locking nut similar to the one denoted by 46.

Referring to the illustration of Fig. l, it will be recognized that the armature assembly, as a whole, is limited to angular movement between y spring 8.

` closed position as shown in Fig. l.

two positions about the geometric axis of the pivot edges. When the magnet coil I5 is deenergized, the armature assembly, under the biasing force of spring 23, is turned clockwise Vaway from the illustrated position so that the vmovable contact member 5 is separated from the stationary contacts 3 and 4 and is forced against the bottom of the contact guide 6 by the Contact When the magnet coil I5 is energized, the armature I I is attracted by the vmagnet and moves the assembly into the illustrated position. Near the end of that movement, the contact member 5 engages the stationary contacts and is arrested while the rest of the armature Vassembly is permitted to perform an additional movement (overtravel). The amount of overtravel is indicated in Fig. 1 by the distance O between two arrowheads. .n Y,

When the contactor is properly adjusted,the pivot point located at I8 in Fig. 1 issubstantially in alignment with the contact surfacessand V.with the mutuallyA engaging surfaces of. magnet and'armature. It will be recognized 'thatjthis 'proper alignment or any departure therefrom .that may be necessary to obtain a desired amount of overtravel can be achieved by displacingfthe bearing bracket I8 relative to the magnet bracket I1 and then fastening it in the correct position.

When assembling the contactor, the magnet brackets I6, I1 and the insulator 2 with the stationary contacts` 3 and 4 are rst secured to the vbase I.' Then the two fastening screws I9 are threaded into the base plate I. The bearing bracket I3 is then placed on the screws I9 by passing it over the reduced portions of the screws by means of the button-hole 43 and the marginal opening 44 (Figs. '7, 8). The bracket I8 is then moved toward the right relative to Fig. 8 in order ,to engage it with the shouldered ends of the screws. Next, the locking screws 20 and 20 are screwed through the openings 25 and 25' (Fig. 2) into the bearing bracket. To adjust the overtravel of the armature assembly to the proper value, the armature assembly may beheld inits Then the L'wo adjusting screws I9,v are turned. With a-,screw driver'from the rear `of base I until the overtravel is correct. Then the adjusting screws. are securely locked in place by the lock nuts, l.46. Thereafter, the bearing bracket I8 is securely .clamped to the magnet bracket I1 byv tightening the screws 2D and 20. Due to the factthat two adjusting screws are used, the bearing bracket can readily be set so that all moving contacts of a multi-pole contactor'touch the stationary contacts simultaneously. By virtue)v of the fact that the armature biasing spring4 23 has its stationary abutment located at the foo'tportion 2l of the bearing bracket I8,k the'proper alignment and positioning of the spring ir'sjnot aifected by the just-mentioned adjustmerit;` of the bracket. The armature assembly thus vmade self-aligning "on its "support "and the"'dis tending at a substantially right angle away from said base surface, a bearing structure having a spring abutment near said base surface and having a portion facing said bracket portion, said bearing structure having a pivot edge parallel to and spaced from said base surface and facing said surface, an assembly having a rigid portion engaging said edge to be angularly movable between two positions about said edge, a compression spring engaging said assembly and said spring abutment for biasing said assembly toward said edge and toward one of said positions, said assembly having an armature adjacent said magnet for moving said assembly to said other position under control by said magnet, said bearing structure being displaceable along said bracket portion toward and away from said base, and fastening means for rigidly securing said bearing structure in a selected position.

2. In a contactor, the combination of a base, an electromagnet, fastening means rigidly connecting said magnet to said base and having a bracket secured to said base and extending at a substantially right angle away from said base, a bearing structure having a spring abutment near said base and having a portion in face-toface engagement with said bracket, said bearing structure having a pivot edge remote from said base and facing said base, an assembly having a rigid structure disposed between said base and said edge and engaging said edge so as to be angularly movable between two positions about said edge, a compression spring engaging said structure and said spring abutment for biasing said assembly toward said edge and toward one of said positions, said assembly having an armature adjacent said magnet for moving said assembly to said other position under control by said magnet, said bearing structure being displaceable along its engaging surface with said bracket toward and away from said base, and fastening screw means traversing said bearing structure and said bracket for firmly securing said structure in an adjusted position and being operatively accessible at a place away from said spring.

3. In a contactor, the combination of a base, bracket means rmly secured to said base and having a bracket extending at a substantially right angle away from said base, an electromagnet attached to said bracket means in spaced relation to said base and disposed at one side of said bracket, an angular bearing structure disposed at the other side of said bracket and having a substantially T-shaped portion adjacent to and facing said bracket and having a foot portion extending away from said bracket and facing said base, said T-shaped portion of said structure having two arms extending laterally beyond said bracket and having mutually aligned pivot edges facing said base, said edges being spaced from and parallel to said base, a pivotally movable rigid cradle, an armature attached to said cradle near said magnet at said one side of said bracket, said cradle having a bifurcated part straddling said bracket as well as said bearing structure at a place between said base and said arms and being in pivotal engagement with said pivot edges, said assembly having an abutment member extending across said bifurcated part at said other side of said bracket, and a compression spring abutting against said foot portion of said bearing structure and against said abutment member of said assembly for biasing said assembly toward said edges and to a pivotal position away from said magnet.

4. In a contactor according to claim 3, said abutment member being separable from said bifurcated part of said assembly, said part having notch means for receiving said abutment member, and said spring being slanted from said foot portion toward said abutment member so as to bias said abutment member into said notch means thus securing said abutment member to said bifurcated part.

5. In a contacter according to claim 3, said T-shaped portion of said bearing structure being in face-to-face contact with said bracket only at a place near said base but being spaced away from said bracket near said arms and edges, said structure having a spacing element located near said arms and abutting against said bracket.

6. In a contacter according to claim 3, said T-shaped portion of said bearing structure being in face-to-face Contact with said bracket only at a piace near said base but being spaced away from said bracket near said arms and edges, said bearing structure being displaceable along said bracket in a direction toward and away from said base, said bracket having two holes elongated in said direction and spaced from each other across said direction so as to lie on both sides respectively of said spring, and two screws operatively accessible from said one side of said bracket and engaging said bearing structure through said respective holes for fastening said bearing structure in an adjusted postion.

RALPH B. IMMEL.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 686,007 Shoemaker Nov. 5, 1901 758,236 Chamberlain Apr. 26, 1904 1,000,314 Zundel Aug. 8, 1911 1,577,031 Kaisling Mar. 16, 1926 2,098,926 Schneider Nov. 9, 1937 2,374,017 Iglehart et al. Apr. 17, 1945 2,409,115 Ellis et al Oct. 8, 1946 2,412,273 King Dec. 10, 1946 2,424,308 Ellis et al July 22, 1947 

